4.0 POTENTIAL COASTAL RECEIVER AREAS

The San Diego shoreline, including the beaches, bluffs, bays, and estuaries, is a significant environmental and recreational resource. It is an integral component of the area’s ecosystem and is interconnected with the nearshore ocean environment, coastal lagoons, wetland habitats, and upstream watersheds. The beaches are also a valuable economic resource and key part of the region’s positive image and overall quality of life.

The shoreline consists primarily of narrow beaches backed by steep sea cliffs. In present times, the coastline is erosional except for localized and short-lived accretion due to historic nourishment activities. The beaches and cliffs have been eroding for thousands of years caused by ocean waves and rising sea levels which continue to aggravate this erosion. Episodic and site- specific coastal retreat, such as bluff collapse, is inevitable, although some coastal areas have remained stable for many years.

In recent times, this erosion has been accelerated by urban development. The natural supply of sand to the region’s beaches has been significantly diminished by flood control structures, dams, siltation basins, removal of sand and gravel through mining operations, harbor construction, increased wave energy since the late 1970s, and the creation of impervious surfaces associated with urbanization and development. With more development, the region’s beaches will continue to lose more sand and suffer increased erosion, thereby reducing, and possibly eliminating their physical, resource and economic benefits.

The State of the Coast Report, San Diego Region (USACE 1991) evaluated the natural and man- made coastal processes within the region. This document stated that during the next 50 years, the San Diego region “…is on a collision course. With sandy beaches backed by sea cliffs, beach erosion and failure of the sea cliffs must be anticipated. Extensive damage and loss of property will occur. While the amount of erosion is dependent upon sea level change, as well as the wave climate, particularly severe storm events,” the report concludes that “all the beaches of the San Diego region are threatened with erosion.” According to the USACE, “…the apparent stability of the beaches is belied by rigorous examination of the historical beach profiles and summation of previous beach nourishment. Without the earlier massive input of beach fill, the shoreline of the San Diego Region would exhibit nearly continuous erosion from Oceanside Harbor to the international border. New sources of beach-quality sand need to be readied for beach nourishment following severe storm events and for long-term protection from rising sea level.”

4.1 Beach Erosion Sites Beach erosion is continually documented by the federal, state, regional, and local governments. The CSMW focuses on addressing statewide sediment management and has systematically inventoried BECAs throughout coastal California, including those of local concern in selected

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areas of the coast. SANDAG is assessing BECAs within the San Diego Coastal RSM Plan region, and inventories of coastal erosion areas are provided in the pages to follow.

4.1.1 State Beach Erosion Concern Areas

The draft California Beach Restoration Survey (2008) presents information about BECAs, including those in the San Diego region provided to CSMW by SANDAG and USACE (Figure 7). These sites have been identified through various data sources including: local surveys done by Cities or SANDAG as part of monitoring programs, extensive analyses by the USACE (1990 and 1991), analyses performed by DBW/SANDAG (1994), a survey conducted by DBW in 2000, and locations currently being investigated for federal interest by the USACE. Recent evaluation of erosion areas was performed by SANDAG and the CSMW as part of the SCOUP (Moffatt & Nichol 2006). The SCOUP program evaluated potential erosion areas and recommended sand placement sites for opportunistic sand. The sites identified by the various efforts listed above are listed in Table 2, and comprise the recommended initial BECAs for this Coastal RSM Plan. Table 2 – Beach Erosion Concern Areas Compiled by the CSMW Reach of Coast Source of Designation North County San Diego/South Oceanside Survey; USACE; CRSMP North Carlsbad State Beach CRSMP Agua Hedionda/Encinas CRSMP South Carlsbad State Beach/Encinas Creek Survey; CRSMP Batiquitos Beaches (in Carlsbad and CRSMP Encinitas) Encinitas/Leucadia Beach USACE; CRSMP Encinitas/Moonlight Beach USACE; CRSMP Cardiff State Beach/San Elijo Lagoon CRSMP Beach Solana Beach/Fletcher Cove USACE; CRSMP Del Mar City Beach/San Dieguito Lagoon CRSMP Beach Torrey Pines State Beach CRSMP Mission Beach CRSMP Ocean Beach (San Diego) CRSMP Coronado CRSMP Imperial Beach USACE; CRSMP Border Field State Park Beach CRSMP Sources: Survey - Location identified in DBWs initial survey of erosion sites USACE - Location under assessment for federal interest CRSMP - Location identified within this Coastal RSM Plan

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Source: CSMW 2008 Figure 7 – State of California Beach Erosion Concern Areas

San Diego Coastal RSM Plan 30 The Mission Beach, Ocean Beach, and Coronado BECAs are less erosive then the others, but they do experience periodic problems during severe winter storm waves.

4.1.2 SANDAG Shoreline Erosion Problem Areas

SANDAG has identified “problem” coastal erosion areas in the SPS (1993) (Figure 8). The problem areas were identified based on existing beach profile surveys by the USACE and observations made by SANDAG member agencies. DBW/SANDAG (1994) inventoried the region and categorized each beach according to its erosional condition. The analysis by SANDAG and DBW was consistent with the SPS.

In North County, the entire reach of coast from Oceanside to La Jolla Shores is considered an erosion problem area. There is a lengthy reach of erosion throughout North County and it requires some sort of remediation in the opinion of SANDAG and its members. The condition of eroding coastal bluffs from La Jolla through Oceanside, with intermittent narrow beaches along low-lying backshore areas near lagoons, supports this conclusion. Another extensive problem area exists throughout Imperial Beach to south of the Mexican Border in South County. USACE research (1990 and 1991) shows a high erosion rate along this reach of coast, and observations by DBW/SANDAG (1994) shows evidence of this erosion. Erosion is documented and observed to the present by monitors and locals.

Mission, Ocean, and Coronado Beaches were not included in the SPS as highly erosive areas as they were wider in the early 1990s than at the present.

4.2 Beach Profiles Beaches are commonly characterized by cross-shore surveys. The resulting profiles represent the elevation of the beach surface and nearshore seabed from the back of the beach to beyond the closure depth. The profile data show seasonal and long-term elevation changes in the beach and nearshore zone. These beach profile data provide information pertaining to the historic and existing sand volumes, beach elevations, and shoreline positions that are useful for planning and design.

SANDAG has recorded beach profiles throughout the Coastal RSM Plan area since 1995, and the USACE recorded profiles from 1934 to 1989. North and South County profile locations are shown in Figures 9 and 10, respectively. Profiles are presently recorded in April/May to measure post-winter conditions and in October to measure post-summer conditions. The beach profiles are used to assess seasonal changes in sand movement on- and offshore, shoreline position, beach retreat or advance, and closure depth. The latest profiles are assumed to represent existing conditions at each sand placement site.

Representative beach profiles from North County (Moonlight Beach), Central County (Mission Beach), and South County (Imperial Beach) are show in Figures 11, 12, and 13, respectively. The profiles tend to be very similar as the sediment grain sizes between the littoral cells show

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Source: SANDAG Shoreline Preservation Strategy 1993

Figure 8 – SANDAG Shoreline Erosion Problem Areas

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Figure 9 – Beach Profile Locations (North County)

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Figure 10 – Beach Profile Locations (Central and South County)

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Source: Coastal Frontiers, 2008 Figure 11 – Beach Profiles for Moonlight Beach (North County)

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Source: Coastal Frontiers, 2008 Figure 12 – Beach Profiles for Mission Beach (Central County)

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Source: Coastal Frontiers, 2008 Figure 13 – Beach Profiles for Imperial Beach (South County)

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little variance because the inland geology is fairly uniform throughout the region’s watersheds, and wave conditions and energy imposed on the profile locations are similar throughout the region.

Depths to the closure of the profiles, or the point at which seasonal changes are no longer discernible, are similar throughout the region (Table 3) (Coastal Frontiers 2007). The slopes of beach profiles out to the closure depth are similar for each site, with a slightly steeper slope in North County than Central and South County.

Table 3 – Beach Profile Data for Representative Beaches

Beach Profile Depth of Beach Profile Percent Slope Designation Closure (Feet, Slope Ratio to MLLW) Moonlight Beach SD-0670 -29 feet 1:34 2.9 Mission Beach MB-0340 -30 feet 1:40 2.5 Imperial Beach SS-0025 -27 feet 1:38 2.6 MLLW: Mean Lower Low Water

The envelopes of the beach profiles show seasonal and long-term extremes in profile elevations, from lower elevations in severe winters to higher elevations during quiet periods and summer. Post-beach nourishment profiles are shown on the figures to depict their elevations after implementation of RBSP I.

4.3 Existing Coastal Sediment Quality Beach sand data were collected for individual coastal cities in support of opportunistic beach fill programs, and for SANDAG as part of the SCOUP I and II Plans (Moffatt & Nichol 2006 and 2008, respectively). The SCOUP I provided guidance and protocol for using opportunistic beach fill as nourishment, and implemented a test pilot program at one location in the region (South Oceanside). Several other SCOUP programs evolved from that initial effort, resulting in SCOUP II, which served to initiate opportunistic beach fill programs at Encinitas, Solana Beach, Coronado, and Imperial Beach. The City of Carlsbad also has an approved opportunistic beach fill program in place that was created separately from the SCOUP efforts and is consistent with the SCOUP approach.

As required for these programs, the envelope of existing sand grain sizes was developed to identify the appropriate gradations that characterize suitable nourishment material for each potential receiver site. Candidate beach fill material is then assessed for suitability against the composite gradation envelope developed for the specific receiver site. Composite gradation envelopes have been developed for seven receiver site locations throughout North and South County. Figures in Appendix C show composite grain size envelopes for Oceanside, Carlsbad, Encinitas, Solana Beach, Coronado, Imperial Beach, and the beach at Border Field State Park near the Tijuana Estuary (Tijuana Estuary South Beach in Table 2), respectively.

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Sand has grain size diameters ranging from 0.074 (very fine) to 4.0 millimeters (mm) (coarse). Most of the region’s beach sand is fine to medium in grain size. North County beaches tend to have slightly coarser sand than do South County beaches, but the difference is minor and they are still similar to each other. Native beach sand in San Diego North County has a median grain size (the mid-point of the gradation range of the material) of between 0.25 and 0.30 mm. The median sand grain size at South County is between 0.20 and 0.25 mm. In winter, cobble can replace sand at many beaches.

Previous data were also collected by the USACE (1984) and Woodward-Clyde Consultants (1998). Their data show that the mean (not to be confused with the median) grain size of native beach sand at these receiver beaches varied, but tended to center on approximately 0.22 millimeters (mm) which is considered fine-grained sand.

4.3.1 Grain Size Homogeneity

Homogeneity is a measurement of how similar the grains in a sample are in size. Heterogenous indicates that grain sizes may range very broadly from very fine to very coarse. When sand exists on the region’s beaches, it is fairly homogeneous as shown in Appendix C. Cobbles periodically exist in addition to sand at some beaches during the winter season, except at Coronado, Mission Beach and Ocean Beach.

Grain size is an indirect indicator of potential chemistry. Homogenous sands have less ability to retain contaminants than do clays and silts. The finer-grained materials contain ionic charges, which attract and hold onto contaminants. The beaches are mainly composed of sand and therefore unlikely to be contaminated. Testing for chemistry at beach receiver sites has not been required for previous permit applications for nourishment, and is not anticipated to be required for future permit phases of projects spawned from this Coastal RSM Plan during future permit phases of this project.

4.3.2 Grain Size Range

References to sand grain size in the previous discussion refer to the high, dry beach area. This is the area that is visible and used by people for recreation, and serves as shore protection for backshore property infrastructure. However, sand grain sizes range more broadly along the receiver site profile from the high dry beach (elevation up to +10 feet relative to MLLW) out to the depth of closure (elevations of approximately -30 feet relative to MLLW). The coarsest sands exist at the highest portion of the beach profile and in the surf zone. The finer sands and other particles (silts and clays) exist on the lower portions of the beach profile, from depths of between approximately -10 feet and -30 feet relative to MLLW. The percentage of fine-grained sediments at lower areas of the beach profile can be up to 35 percent or more. The percentage of fine-grained sediments located within the higher portion of the beach profile is typically below 5 percent.

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4.3.3 Sediment Color

Sediment color has been an issue for certain previous projects using upland sand. The color of existing beach sand in the region is basically beige with some areas of darker-colored materials that consist of mica. Fletcher Cove in Solana Beach and beaches at the base of Torrey Pines bluffs near Black’s Beach in San Diego sometimes possess very dark colored material. Remaining beaches in the region typically consist of the lighter-toned beige color.

Dredged material and many upland source materials initially are typically darker colored than the receiving beach. When placed in the surf zone, the material is washed and reworked by waves resulting in sand similar in appearance to the receiving beach. Color was addressed in the SCOUP I (Moffatt & Nichol 2006) by requiring material from upland to be placed below the mean high tide line so that tides and waves would rework the sediment. This reworking process adequately distributes and disperses the sediment such that source sand with a different color than the receiving beach is no longer discernible.

Resource agencies have been less concerned about material color in the past because of more extensive use of dredged material for historic beach fill rather than upland material. Strong public reaction occurred in 1996 when red-colored upland sand was placed over the white sand beach at Ponto Beach in Carlsbad, California (Sherman, et al. 1998). Permit agencies have informally indicated that their only criteria for color is to reasonably match the color of the receiving beach after reworking by waves.

4.4 Existing Coastal Habitat Constraints Existing coastal habitat constraints are described below as an overview, a summary, and for impact considerations.

4.4.1 Overview of Coastal Habitats

The coastline of San Diego County includes a variety of habitats including sandy beaches and subtidal, nearshore and offshore reefs, estuarine lagoons, and larger embayments. In addition, coastal dune/strand and eelgrass meadows locally occur along the coast. Within these coastal areas, biota differ among sandy, rocky, and vegetated habitats. Generally, rocky and vegetated marine habitats are rarer in occurrence and support greater biological diversity than soft-bottom habitats. Federally designated habitats of particular concern (HAPCs) include estuaries, canopy kelp, seagrass, and rocky reefs. Other sensitive resources include endangered and threatened species protected under the Endangered Species Act (ESA).

The Marine Life Management Act (MLMA) was passed in 1999 by the California Legislature to ensure the conservation, restoration, and sustainable use of California’s marine living resources (http://www.fgc.ca.gov/mlma/mlma.html). The MLMA requires that Fishery Management Plans (FMPs) form the primary basis for managing the state’s marine fisheries. The California DFG prepared a Master Plan for developing FMPs that lists over 375 species of fish, invertebrates, and plants managed by the state (www.dfg.ca.gov/marine/masterplan). Two FMPs have been

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prepared by DFG, including the Nearshore FMP, which covers 19 species of finfish, and the White Seabass FMP (www.dfg.ca.gov/marine). Several other state-managed species are covered in federal FMPs that are regulated by the National Marine Fisheries Service (NMFS), including: Coastal Pelagic Species, Highly Migratory Species, Pacific Coast Groundfish, and Pacific Coast Salmon (www.pcouncil.org).

Also in 1999, the California State Legislature adopted the Marine Life Protection Act (MLPA), which requires the state to design and manage a network of marine protected areas in order to, among other things, protect marine life and habitats, marine ecosystems, and marine natural heritage, as well as improve recreational, educational and study opportunities provided by marine ecosystems (http://www.dfg.ca.gov/mlpa/). This initiative includes evaluation and/or re-design all existing state marine protected areas (MPAs) and potentially the creation of new MPAs. MPA designations include: state marine reserve (SMR), state marine park (SMP) and state marine conservation area (SMCA). The state is divided into three coastal region study areas for this process. The planning process for the south coast study region, which ranges from Point Conception to the border with Mexico, began in mid-2008 and is currently ongoing. The outcome of this planning effort for the San Diego region may be an important consideration of future sand management activities.

Section 4.4.2 summarizes sensitive resource constraints, including managed species (e.g., grunion, lobster) for the San Diego region, while impact considerations are discussed in Section 4.4.3.

4.4.2 Summary of Biota Constraints

Figures 14 to 21 illustrate locations of existing, historical, and proposed CRSM Plan sites with respect to biological constraints such as rocky vegetated reefs, surfgrass, lagoons, and nesting or wintering areas of the California least tern (Sterna antillarum browni) and western snowy plover (Chardrius alexandrinus nivosus). Vegetated reefs are distinguished according to dominant vegetation (i.e., surfgrass, understory algae, giant kelp). The extent of kelp canopy can vary each year depending on environmental conditions; therefore, recent and historical locations of kelp canopies are provided on the figures.

Other sensitive resources occur or have the potential to occur, but are not shown on the figures. For example, the endangered California brown pelican is a visual predator of fish in the nearshore and rests on structures (e.g., jetties, floats, docks) and rocks away from human disturbance. Several species of abalone (Haliotis spp.) that are endangered, candidate listed species, or otherwise protected occur in association with some of the more developed nearshore reefs in the County. Endangered whales and other marine mammals (seals, sea lions, dolphins, and porpoises) are also afforded protection under the Marine Mammal Protection Act.

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Figure 14 - Sensitive Biological Resource Areas in the Vicinity of Oceanside Sediment Management Areas

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Figure 15 - Sensitive Biological Resource Areas in the Vicinity of Carlsbad Sediment Management Areas

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Figure 16 - Sensitive Biological Resource Areas in the Vicinity of Carlsbad and Encinitas Sediment Management Areas

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Figure 17 - Sensitive Biological Resource Areas in the Vicinity of Encinitas and Solana Beach Sediment Management Areas

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Figure 18 - Sensitive Biological Resource Areas in the Vicinity of Del Mar and Torrey Pines Sediment Management Areas

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Figure 19 - Sensitive Biological Resource Areas in the Vicinity of Mission Beach Sediment Management Areas

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Figure 20 - Sensitive Biological Resource Areas in North San Diego Bay in the Vicinity of Coronado Sediment Management Areas

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Figure 21 - Sensitive Biological Resource Areas in the Vicinity of Imperial Beach Sediment Management Areas

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Several state-managed species of commercial or recreational importance are associated with hard bottom or vegetated habitats such as California spiny lobster (Panulirus interruptus) and sea urchins (Stronglyocentrotus spp.). Management regulations associated with protection of hard bottom and vegetated HAPCs generally are protective of associated species. Several other state- managed species are associated with sandy beach or subtidal habitats. For example, California grunion (Leuresthes tenuis) spawns on sandy beaches of suitable habitat quality in the region. Pismo clam (Tivela stultorum) may occur in localized beds in subtidal sands and in the intertidal zone of some beaches.

Generally, sensitive habitats, sensitive species, and areas of concentration of state-managed species represent constraints for sand management activities. Avoidance of direct impacts is a primary consideration. In addition, distances may be specified by permits to protect such resources from indirect impacts such as increased noise, turbidity, and other human disturbances associated with sand management activities.

Table 4 summarizes the regional distribution of habitats in San Diego County, and sensitive resource constraints in the vicinity of potential sand receiver sites are listed in Table 5. Other sensitive aquatic resources (e.g., Pismo clam beds) potentially occur in the vicinity of receiver sites; however, there is a lack of available information on their occurrence. A more detailed summary on proximity of selected sensitive resource to potential receiver sites is given in Appendix E.

Table 4 - Regional Distribution of Habitats in San Diego County

Habitat Relative Occurrence San Diego County

ƒ Coastal Dune and ƒ Localized areas ƒ North of Santa Margarita River, strand remnants near lagoons (e.g., Batiquitos, San Elijo, San Dieguito, Los Penasquitos), Coronado Beach, Silver Strand, Imperial Beach ƒ Sandy Beach ƒ Majority of shoreline ƒ Majority of shoreline ƒ Sandy Subtidal ƒ Majority of nearshore ƒ Majority of nearshore ƒ Nearshore Reefs ƒ Localized areas ƒ Limited Oceanside; localized off Carlsbad, Encinitas, Solana Beach, Del Mar, Torrey Pines, La Jolla, Pacific Beach, Ocean Beach, Sunset Cliffs, Point Loma, Imperial Beach ƒ Offshore ƒ Localized areas ƒ Oceanside, Torrey Pines, Coronado, Cobbles/Rocks Imperial Beach ƒ Surfgrass Beds ƒ Localized areas on ƒ Carlsbad, Encinitas, Solana Beach, Del rocky intertidal and Mar, Torrey Pines, La Jolla, Pacific subtidal nearshore Beach, Ocean Beach, Sunset Cliffs, Point reefs Loma

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(cont.) Habitat Relative Occurrence San Diego County

ƒ Eelgrass Meadow ƒ Localized areas in ƒ Aqua Hedionda Lagoon, Batiquitos bays and sheltered Lagoon, Mission Bay, San Diego Bay, coastal areas Zuniga Point ƒ Kelp ƒ Localized areas on ƒ Carlsbad, Encinitas, Solana Beach, Del Forests/Beds subtidal nearshore Mar, Torrey Pines, La Jolla, Pacific and offshore reefs Beach, Ocean Beach, Sunset Cliffs, Point Loma, Imperial Beach ƒ Lagoons ƒ Six ƒ Buena Vista, Aqua Hedionda, Batiquitos, San Elijo, San Dieguito, Los Penasquitos ƒ Rivers ƒ Four ƒ Santa Margarita, San Luis Rey, San Diego, Tijuana ƒ Bays/Harbors ƒ Three ƒ Oceanside, Mission Bay, San Diego Bay

Table 5 - Sensitive Biota Near Sediment Management Receiver Sites

ID Receiver Sites

itat b Ha Surfgrass Nearshore Reef Bay/Lagoon Inlet Bay/Lagoon Offshore KelpBed Least Tern Nesting California Grunion Coastal Dune/Strand Snowy Plover Nesting Snowy Plover Snowy Plover Critical Snowy Plover or Outfall Pipeline (O) Other Rocks ®, Pier(P), Snowy Plover Wintering Snowy Plover Constraint Distance1 2640 2640 2640 3 02 2640 0 3000 1500 1500 3 1. South Oceanside onshore √ 2. South Oceanside √ √ R/P nearshore* 3. North Carlsbad onshore √ √ √ √ √ √ 4. Agua Hedionda onshore √ √ √ √ √ √ 5. South Carlsbad onshore √ √ √ √ √ 6. Batiquitos Beach onshore √ √ √ √ √ √ √ √ √ √ 7. Batiquitos nearshore * √ √ √ √ √ 8. Leucadia onshore √ √ √ √ √ 9. Moonlight Beach onshore √ √ √ √ 10. Cardiff Beach onshore √ √ √ √ √ √ 11. Cardiff nearshore* √ √ √ O+ √ 12. Solana Beach (Fletcher √ √ √ √ Cove) onshore 13. San Dieguito nearshore* √ √ O+ √ 14. San Dieguito onshore* √ √ √ √ √

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15. Del Mar onshore √ √ √ √ √ √ (cont.) ID Receiver Sites

itat b Ha Surfgrass Nearshore Reef Bay/Lagoon Inlet Bay/Lagoon Offshore KelpBed Least Tern Nesting California Grunion Outfall Pipeline (O) Coastal Dune/Strand Snowy Plover Nesting Snowy Plover Snowy Plover Critical Snowy Plover Snowy Plover Wintering Snowy Plover Other Rocks ®, Pier(P), or

16. Torrey Pines onshore √ √ √ √ √ √ √ √ 17. Torrey Pines nearshore* √ √ O √ 18. Mission Beach onshore √ √ √ 19. Mission Beach nearshore* √ √ O+ √ 20. Ocean Beach onshore* √ √ P √ √ √ √ 21. Coronado Beach onshore √ √ √ √ √ 22. Coronado Beach nearshore 23. Imperial Beach onshore √ √ √ √ √ √ √ 24. Imperial Beach nearshore √ √ P (N) 25. Imperial Beach nearshore √ √ P, R++ √ (S) 26. Tijuana Estuary onshore √ √ √ √ √ √ √ Sources: Figures 14-21; + = MEC 2000; ++ SAIC 2009; * = new site that has not received prior sand placement Constraint Distance Notes: 1 = Constraint distance based on RGP 67 guidance or interpretation of guidance (i.e., although no specific distance was specified for reef, surfgrass, or kelp areas, monitoring requirements for turbidity is specified within ½ mile offshore and downcoast of sand placement). 2 = No reported criteria; constraint distance based on avoidance of direct impact (i.e., 0 ft) 3 = No reported criteria; constraint distance to be based on site- or project-specific conditions

4.4.3 Biota Impact Considerations

Several types of impact concerns on biota have been identified in reviews of dredging or beach nourishment (Hirsch, et al. 1978; Wright 1978; Naqvi and Pulllen 1983; LaSalle, et al. 1991; NRC 1995; Greene 2002). Most are associated with the construction phase of sand management and relate to the potential to damage sensitive habitats or interfere with critical life functions of sensitive species from equipment, sand removal, or sand placement. CSMW’s draft Biological Impacts Analysis report (Science Applications International Corporation or SAIC, in progress) contains an exhaustive review of potential impacts associated with sand management, as well as recommendations on how to minimize adverse impacts during planning and implementation of the project. Impact considerations from that report are presented below.

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Several activities and/or measures may be taken during the pre-construction phase to minimize adverse effects associated with implementation of sand management projects. An important consideration during project design is to locate sand management project sites to avoid direct impacts to sensitive habitats and to allow sufficient buffer distances or volume limitations to minimize the extent or duration of impacts away from the site associated with noise, sedimentation, or turbidity. During the project phase an important permit requirement is testing to determine compatibility of source sediments with those of the receiver site(s). SCOUP programs that permit use of less-than optimum sands at certain sites within the region also specify sediment testing after construction to ensure evaluation and long-term protection of beneficial uses of sandy beach habitats. Depending of site conditions, focused pre-construction surveys may be necessary to support scheduling, limits of construction corridors in environmentally constrained areas, verification of habitat suitability for grunion spawning, or presence/absence of sensitive resources that would require implementation of additional mitigation measures during construction.

Potential impact considerations during the construction phase include: ƒ Burial or removal of sensitive habitat or biota; ƒ Removal or damage to sensitive habitats or biota from equipment operation (dredges, pipelines vehicles, vessels); ƒ Disturbance or interference with movement, foraging, or reproduction of sensitive species from equipment operation; and ƒ Turbidity or water quality degradation associated with dredging or sand placement to displace or interfere with foraging, respiration, recruitment, or reproduction of aquatic animals, or degradation of vegetated habitats.

After sand placement, impact concerns relate to recovery rates of soft-bottom habitat functions, and the potential for sand, moved by waves and currents, to become trapped or build up in sensitive habitat areas, if present nearby. Potential impact considerations after construction include: ƒ Compatibility of placed sands with existing sediments; ƒ Potential for alteration of hydrodynamics and habitat quality; ƒ Sedimentation and degradation of nearshore reefs; ƒ Sedimentation and degradation or loss of surfgrass beds; ƒ Sedimentation and degradation or loss of offshore kelp beds; ƒ Sedimentation that results in substantial shoaling or closure of lagoon inlets; and ƒ Sedimentation that increases the frequency or volume of maintenance dredging in lagoons or harbors.

Potential impacts may have adverse, beneficial, or no effect on habitats or species depending on timing of activities, magnitude of effect, or vulnerability or tolerance to disturbance. Consequently, locations of sensitive habitats and resources may constrain volume, schedule, or frequency of sand management activities. The following subsections summarize primary impact

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considerations associated with selected sensitive habitats and resources of particular concern for coastal sand management activities in San Diego County.

Sandy Beach and Subtidal Habitats

The intertidal portion of sandy beaches is inhabited by a variety of invertebrates (e.g., worms, sand crabs, clams), which provide forage for shorebirds along the shore and fishes in the surfzone. California grunion uses suitable sandy beaches as spawning habitat. The threatened snowy plover forages, nests, and winters on certain beaches in the County (Table 5, Figures 14- 21). Beaches also may be used as resting habitat for seabirds and pinnipeds (seals, sea lions).

Subtidal sands support a greater variety of invertebrates, which provide forage for bottom- associated fish. Generally, the diversity of invertebrate assemblages is less in the energetic surf zone and increases as the energy decreases with increasing distance offshore. Subtidal areas may vary in development of nearshore resources depending on physical conditions and disturbance frequency (e.g.,

near river outlets). Certain areas also may have unique Shorebirds foraging at nourished San Diego resource concentrations (e.g., Pismo clam beds). beach Photograph by Karen Green, SAIC Many coastal fish species make inshore/offshore migrations, using shallows as spawning or nursery habitats (Cross and Allen 1993). For example, California halibut migrates inshore in late winter and early spring to spawn and remain in shallow waters until late fall and winter (Love 1996).

Sand placement in aquatic habitats will bury invertebrates with limited mobility and dredging removes sedentary invertebrates. Generally, invertebrate assemblages recover within a season in areas subject to frequent disturbance (e.g., beaches, areas subject to maintenance dredging); however, recovery may take substantially longer in less-disturbed habitats. Although sandy beach invertebrates are adapted to seasonal changes in disturbance and sand level, unnatural timing or frequency of disturbance may slow recovery rates and reduce the forage base for shorebirds. A change in disturbance frequency also has the potential to affect recovery of subtidal assemblages. Other factors such as sediment compatibility, sedimentation, hydrodynamics, timing relative to recruitment periods, and distance between disturbed and undisturbed areas may influence invertebrate recovery rates (Reilly and Bellis 1983; Rackosinski, et al. 1996; Newell, et al. 1998; Petersen, et al. 2002; Versar 2004). Sediment compatibility also may influence shorebird foraging by indirectly affecting the invertebrate forage base or by interfering with prey capture (Greene 2002; Peterson, et al. 2002).

Sandy beach habitat may be enhanced by beach nourishment in erosive beach areas (Melvin, et al. 2001, CZR 2003, SAIC 2006). Sand is the limiting factor associated with seasonal development of the invertebrate community and functional use of the beach for spawning by grunion and foraging, resting, or nesting by shorebirds. Beach nourishment may enhance habitat suitability or functions in erosive beach areas.

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Sand management considerations for sandy beach or subtidal habitats include: ƒ Compatibility between source sands and native sands; ƒ Timing of onshore activities relative to invertebrate recruitment periods; ƒ Proximity to critical habitat, nesting areas, or winter concentrations of snowy plovers; ƒ Frequency of disturbance; ƒ Potential for modification to hydrodynamics or physical habitat conditions; ƒ Potential for cumulative impacts associated with change in disturbance frequency; and ƒ Occurrence of unique resource areas (e.g., Pismo clam beds).

Reefs and Offshore Rocks

Rocky habitats are localized in southern California. Habitat values and functions may vary considerably among hard bottom areas depending on physical characteristics and degree of sand influence. Reef height and complexity are primary factors associated with habitat quality (Ambrose, et al. 1989). Nearshore and intertidal reefs are subject to sand influence within the littoral zone from natural seasonal on- and offshore sand migration. Low-lying Close-up view of sand-scoured intertidal reef reefs subject to sand scour support few biota. Photograph by Karen Green, SAIC Similarly, cobbles subject to sand scour and tumbling from wave action support few biota.

In contrast, reefs that extend above the height of seasonal sand movement generally support diverse communities of invertebrates, fish, and vegetation, including commercially important plants (e.g., giant kelp) and animals (e.g., lobster, sea urchins, sea cucumbers, and reef-associated fish). Hard bottom areas also attract recreational sport diving, fishing, and educational interest. Coastal birds may forage on invertebrates or fish associated with rocky intertidal Nearshore reef off Encinitas habitats. Intertidal rocky areas also may provide Photograph by Danny Heilprin, SAIC important resting areas for pinnipeds (sea lions, seals). Vegetated hard-bottom habitats of particular concern include surfgrass beds in intertidal and shallow subtidal waters and kelp forests in deeper nearshore waters (see subsections below).

Sand management impact considerations for rocky reefs/offshore rocks include: ƒ Potential for substantial turbidity or sedimentation based on sand volume and proximity of sand management activities; ƒ Reef heights and habitat quality; and ƒ Existing uses (e.g., commercial or recreational fishing, diving, education areas).

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Surfgrass Beds

Surfgrass grows on rocky habitats from low intertidal to subtidal depths. Two species occur off the coast of California, Phyllospadix. scouleri with short flowering stems and P. torreyi with long flowering stems. Although surfgrass may range to depths of 50 feet, beds become patchy and gradually disappear below 23 feet (Williams 1995). Although surfgrass is a flowering plant that produces seeds, development of surfgrass beds is largely by vegetative propagation of the rhizomatous root system. Because this is a slow process, reestablishment of surfgrass beds may take years if the rhizome mat is removed or dies.

Surfgrass beds are ecologically sensitive, supporting a variety of habitat functions including foraging habitat for fish and birds, sheltering habitat for fish, and nursery habitat for several species including the commercially important California spiny lobster (Panuliris interruptus). Great egrets foraging on surfgrass habitat Photograph by: Karen Green, SAIC Surfgrass is adapted to seasonal sand movement in shallow water and is considered a sand tolerant species (Littler, et al. 1983). Surfgrass also is considered a beach builder, stabilizing beaches by binding sands with its rhizomatous roots (Gibbs 1902). However, excessive sedimentation that results in prolonged or substantial burial of leaves reduces photosynthesis and growth and may lead to habitat degradation or loss (Reed, et al. 2003).

Although surfgrass may recover relatively quickly from small-scale disturbance by vegetative expansion, recovery can take years if there is substantial disruption or loss of the rhizome mat. Artificial reestablishment of surfgrass beds using seeding or transplants is technically feasible, but has not been demonstrated beyond an experimental scale. Therefore, the effectiveness of compensatory mitigation to restore habitat loss is unknown. These uncertainties, as well as the potential for impacts to have long-term consequences, are primary constraints for sand management projects when surfgrass habitat occurs nearby.

Sand management impact considerations for surfgrass include: ƒ Potential for substantial sedimentation based on sand volume and proximity of sand management activities; ƒ Reef heights on which surfgrass occurs; and ƒ Potential for equipment damage from pipelines or vehicles.

Underwater view of kelp forest Photograph credit: San Diego Nearshore Program http://nearshore.ucsd.edu/

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Kelp Forests/Beds

Giant kelp forests, with their extensive vertical structure, represent the most diverse of the marine habitats and support commercial fisheries, education, and recreation. Kelp forests/beds are dynamic, with substantial variability in extent of surface canopy between years associated with storms and other oceanographic conditions (e.g., El Niño Southern Oscillation). Although many functional values are tied to the presence of kelp canopy, habitat values persist in the absence of canopy (e.g., understory and bottom-dwelling algae, invertebrates, and cryptic fish species). Therefore, constraints maps in this document are based on historic occurrence and substrate.

Kelp plants are vulnerable to vessel impacts (propellers, anchoring) resulting in frond entanglement or dislodgement of holdfasts. Kelp forest and associated understory vegetation also are sensitive to changing light levels and are limited when light transmission is substantially impaired. Light reduction does not have an impact on adult plants with surface canopies, but can reduce establishment of early life stages and growth of juvenile plants. Therefore, turbidity from sand management is of potential concern if substantial or prolonged.

Kelp forests are highly vulnerable to sedimentation impacts, which can potentially damage plants from abrasion and scour or preclude recruitment when sediment accumulates on hard substrate. Kelp forests primarily occur outside the littoral zone, but may experience sedimentation during high wave conditions (e.g., storms, El Niño). Inshore boundaries of kelp forests, which may extend to shallower waters during mild oceanographic conditions, are most vulnerable to sedimentation and dislodgement during storms.

Understory kelp occurring inshore of kelp forests are adapted to the relatively harsh environmental conditions in the littoral zone, including sedimentation. However, inshore kelp requires hard substrate for attachment; therefore, persistent sedimentation may lead to habitat degradation or loss. Long-term impacts would not be expected from transient sedimentation given the opportunistic life histories of many inshore kelp species.

Sediment management impact considerations for kelp forests/beds include:

ƒ Potential for substantial sedimentation based on sand volume and proximity of kelp forests/beds; ƒ Potential for prolonged turbidity over kelp bed areas; and ƒ Potential for equipment damage from vessels and anchoring.

Eelgrass Meadows

Eelgrass is a marine vascular plant consisting of subsurface rhizomes and above ground leaves. Eelgrass forms submerged Close-up view of eelgrass Photograph by SAIC beds, also termed meadows, in protected waters. Eelgrass

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primarily occurs in bays and lagoons in San Diego County, although a persistent meadow also occurs at Zuniga Point near the entrance of San Diego Bay. Although eelgrass may ranges from low intertidal to depths up to 100 feet, light limitation generally results in shallow depth distributions. Similar to surfgrass, eelgrass primarily expands by vegetative propagation of the rhizomatous subsurface mat (Phillips 1984, NOAA 2001b). Eelgrass is a special aquatic site (SAS) (i.e., vegetated shallows) under Section 404(b) (1) of the federal Clean Water Act.

In southern California, eelgrass may grow year round, although beds exhibit some die back (bed thinning) in winter with reduced leaf density and slowed growth (Ware 1993, MEC 2000b). Eelgrass meadows are used as spawning or nursery areas for many commercially and recreational important finfish and shellfish species, including California halibut, California spiny lobster, sand bass, and surfperch (Hoffman 1986, Ware 1993). Eelgrass meadows also are used as nursery areas for small forage fish (anchovies, silversides), which are preyed upon by the endangered California least tern.

Eelgrass leaves generally are shorter in the intertidal and longer at subtidal depths, ranging from several inches to > 3 feet in southern California (Phillips 1984, Ware 1993). Long, buoyant leaves facilitate photosynthesis under naturally varying light conditions. During periods of active growth, carbohydrate reserves are stored in leaves, rhizomes, and roots that may be used to support metabolism during periods of light limitation (Zimmerman, et al. 1995; Burke, et al. 1996).

Eelgrass beds are slow to recover from sand disruption rhizomes removal, and seed bank removal. Limited seed dispersal can affect natural recovery rates, and colonization by vegetative reproduction is very slow (Orth, et al. 1994, 2006). Recovery may be faster if plant loss affects above ground leaves, but does not affect the rhizomes or the seed bank. Eelgrass habitat loss requires replacement consistent with the Southern California Eelgrass Mitigation Policy (www.http://swr.nmfs.noaa.gov/hcd/policies/EEPO). Sediment management impact considerations for eelgrass include: ƒ Potential for substantial sedimentation based on sand volume and proximity of eelgrass meadows; ƒ Potential for prolonged turbidity; and ƒ Potential for equipment damage from dredges, pipelines, and vessels.

Coastal Dune or Strand

In California, native coastal strand vegetation is designated as rare. Coastal dune or strand habitat has been substantially modified from development, human use, and historical practices involving use of invasive exotic species to stabilize dunes. Beaches with high public use, or limited sand supply and erosive conditions, often lack

coastal strand vegetation on the backshore or adjacent Limited coastal strand near Batiquitos coastal dunes. Consequently, functional coastal strand Photograph by Karen Green, SAIC backshore or dune habitat only occurs in localized areas.

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Coastal dune or strand vegetation are adapted to withstand the stress associated with winds, shifting sands, salt spray, and poor water-holding capacity and low fertility of the sandy sediment. Vegetation generally has low stature, deep or rhizomatous roots, and dense growth patterns that help anchor and protect individual plants from shifting sands and winds (CNPS 1996). However, coastal dune or strand habitat is highly vulnerable to human impacts both from foot traffic and vehicle use.

Coastal dune/strand habitat may support several endangered, threatened, and other rare plant species (CalFlora 2006). Threatened western snowy plover and endangered California least tern may nest in foredune habitat (CCC 1987, USACE 2003).

Sand management impact considerations for coastal dune/strand habitats include: ƒ Potential for damage or removal of native vegetation by equipment or human disturbance; and ƒ Potential to interfere with foraging or reproductive functions of sensitive wildlife that may use this habitat.

California Grunion

Grunion is a pelagic, schooling fish that generally dwells off sandy beaches from just seaward of the surf line to a depth of approximately 60 feet. Grunion feed on small planktonic organisms and are prey to predators such as larger fishes, California least tern, and marine mammals

(Love 1996, Gregory 2001, Martin 2006). Grunion eggs Grunion spawning are preyed upon by shorebirds, various invertebrates Photograph by Doug Martin (worms, insects), and ground squirrels (Martin 2006). Grunion are an endemic species with a very limited habitat range. Sandy beaches are essential fish habitat for this unique California species. San Diego County comprises roughly a third of the entire spawning habitat area for this fish in California (Martin, K., personal communication)

Between late February and early March, California grunion spawn on beaches in southern California; however, spawning may extend through early September (Fritzsche, et al. 1985; Martin 2006). Grunion may spawn on any or all of the 4 to 5 nights following full and new moons (e.g., spring tides), beginning a little after high tide (Gregory 2001, Martin 2006). CDFG makes available each year the predicted grunion runs from March through August. A recreational fishery for grunion occurs during spawning runs during March and June-August; the fishing season is closed in April and May.

During spawning, grunion swim as far up the beach as possible on the breaking wave. These fish spawn above the mean high tide line but below the highest high tide line; beaches that are inundated at an extreme high tide may still support grunion runs as the tide ebbs, either later that night or on subsequent nights. However, narrow beaches that are inundated by high tides across

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the spring high tide series associated with predicted multi-day grunion runs would not support successful egg incubation if spawning did occur.

The female excavates the semi-fluid sand with her tail and buries herself up to her pectoral fins. Males mate by curving around a female and releasing their milt as she deposits her eggs. Sand from receding waves covers the eggs to a depth of 6 to 8 inches over the next several days (Smyder and Martin 2002); although burial depths up to 18 inches have been reported (Fritzsche, et al. 1985). Eggs incubate in the sand about 10 days until the spring tides reach them, but incubation may extend an additional four weeks if necessary (Martin 1999, Griem and Martin 2000, Smyder and Martin 2002). Mechanical agitation by wave action triggers hatching (Griem and Martin 2000).

Habitat suitability for spawning may vary seasonally in association with natural erosion and accretion cycles. On erosive beaches, habitat suitability may span fewer months than the grunion spawning season. Beach nourishment was found to extend habitat suitability across the spawning season at several sites in Encinitas after RBSP I (SAIC 2006). Thus, beach nourishment may actually benefit California grunion by creating or expanding sandy beach spawning habitat.

Primary concerns regarding impacts to grunion are that beach nourishment will disturb, bury, or otherwise adversely affect spawning success. Turbidity also has the potential to affect adult fish during sand management activities, due to these planktivorous fish aggregating for spawning and feeding in the nearshore.

Substrate compatibility is an important consideration for habitat suitability. Fine sediments can block interstitial spaces in the sand and prevent adequate oxygenation of eggs (Martin and Swiderski 2001). However, critical impact thresholds with respect to substrate characteristics are unknown. Beach slope also may be important. Steep slopes or scarps may inhibit spawning or limit egg survival. Narrow beach width or slopes that are too flat could result in egg wash out or saturation. The effects of increased fine sediment on nearshore spawning aggregations and feeding for these planktivorous fishes are unknown.

Sediment management impact considerations for California grunion include: ƒ Schedule of activities relative to spawning season (March 1-August 31); ƒ Habitat suitability for spawning; ƒ Compatibility of placed sands and fill design (e.g., slope) with habitat suitability; ƒ Sand placement and equipment operation in spawning habitat; ƒ Monitoring for occurrence of grunion spawning activity up to two weeks prior and during sand placement; and ƒ Potential to enhance suitability of spawning habitat.

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Snowy Plover

Western snowy plover is a federal threatened species and California Species of Special Concern. Critical Habitat has been designated at several beaches in San Diego County (Table 5, Figures 14-21). The USFWS also has identified locations where habitat may be suitable to support wintering concentrations (wintering areas), although information on actual use

is limited. Potential wintering areas shown on Western Snowy Plover Figures 14-21 are from the 2007 Recovery Plan for Photograph by Callie Bowdish the Pacific Coast Population of the Western Snowy Plover. It also is possible that other locations than shown in the 2007 Recovery Plan may be used for wintering, such as Buena Vista Lagoon and Torrey Pines State Beach – Blacks; prior nesting also has occurred on South Carlsbad State Beach and other areas of the Silver Strand than shown on Figure 20 (USFWS, 2009 personal communication). The breeding season for western snowy plovers extends from early March to late September.

Snowy plovers nest on sparsely vegetated sands at beaches, creek and river mouths, created dredge spoil islands, flats of salt evaporation ponds, and salt pannes in lagoons and estuaries (Miller, et al. 1999). Nests are depressions in the substrate lined with bits of debris or shells and may be scattered throughout an area rather than in defined colonies. Human use of nesting beaches has been the greatest factor in the decline of the western snowy plover (Bruce, et al. 1994).

Snowy plovers feed on sand crabs, sand hoppers, flies, beetles, brine shrimp, and other aquatic and terrestrial invertebrates. On beaches, snowy plovers probe for crustaceans and worms in the low-tide zone, search for insects and other small invertebrates among debris (especially drift kelp) along the high-tide line, or probe the sand under low foredune vegetation (Lafferty 2000).

Snowy plovers have cryptic coloration and tend to crouch in depressions, which makes them very hard to notice unless they move. This increases their vulnerability to being run over by vehicles or being trampled (Lafferty 2000). These birds are relatively tolerant of humans at distances greater than 100 feet (Lafferty 2000, 2001).

Sand management projects may require consultation with the USFWS and USACE under Section 7 of the ESA if activities would occur in or adjacent to critical habitat, during the breeding season, or in areas of wintering concentrations. Sand management impact considerations for western snowy plover include:

ƒ Schedule of activities relative to the breeding season (March 1-September 30); ƒ Proximity to nesting areas; ƒ Potential for disturbance near nesting areas or in areas where there are wintering concentrations of birds; ƒ Compatibility of placed sands in areas adjacent to critical habitat and wintering areas; and ƒ Potential to enhance wintering and critical habitat locations.

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California Least Tern

California least tern is a state and federal listed endangered species. Least terns breed in colonies on sparsely vegetated sandy beaches, flats of salt evaporation ponds, created dredge spoil islands, and non-beach sandy surfaces in coastal areas (Figures 14-21). California least terns are only present in California during the breeding season of April through September (Atwood, et al. 1994).

Least terns feed on small surface schooling fishes such as California Least Tern topsmelt, northern anchovy, jacksmelt and mosquitofish. Photograph by Kathy Keane They are opportunistic in their foraging behavior and may shift locations in response to localized concentrations of suitable prey (Atwood and Minsky 1983). They forage in the ocean from just beyond the surf line to up to 1 to 2 miles out to sea (Collins, et al. 1979), although they have been documented to forage up to five miles from the nesting colony (USFWS 2000). The majority of least tern foraging is within 1 mile of shore in waters less than 60 feet deep (Atwood and Minsky 1983, AMEC 2002). During the breeding season, California least terns depend on an adequate supply of small fishes near their breeding colonies. When the adults forage away from their nests, young are left unprotected and vulnerable to predation.

Sand management projects may require consultation with the USFWS and USACE under Section 7 of the ESA, particularly if activities would be within 1 mile of nesting colonies during the breeding season. RGP 67 restricts activities within 3,000 feet of breeding colonies. Because least tern nesting areas occur at several locations along the coast of San Diego County, the USFWS should be contacted to determine if consultation would be necessary for any sand management project proposed during the tern breeding season (USFWS, 2009 personal communication). Sand management impact considerations for California least tern include: ƒ Schedule of activities relative to the breeding season (April 1-September 30); ƒ Proximity to breeding colonies; and ƒ Potential for turbidity from sediment management activities interfering with foraging activities near breeding colonies.

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